Jan 22, 2013

What Causes Gray Hair

A few of these gray things have
begun to sprout and it made me wonder why. A person’s hair color is
the result of pigments known as melanin produced by a specialized
group of cells known as melanocytes. Melanocytes are found
throughout our body and the melanin they produce is what gives our
skin, hair, and eyes their color. Scientists can determine what
color your eyes and hair are from DNA.

The melanocytes responsible for hair color are found in the bulbs of
your hair follicles.
There are two main types of melanin. Eumelanin produces dark browns
and blacks, and pheomelanin produces reddish/yellow. How these cells
blend together determines what color hair will be. It is not fully
known what makes the melanocytes blend together in the ways they do,
but it appears to be genetic.

Once melanin is produced, their granules are transferred to adjacent
keratinocytes, also found in the bulbs of your hair follicles.
Keratinocytes are what produce keratine, the dead protein cells that
make up our visible hair. Gray hair is the result of less melanin
within the keratin. The less melanin, the more gray your hair will
be and white hair has no melanin.

As we age our melanocytes decrease in number. The result is less and
less melanin, until none are present, so hair slowly turns gray, and
then white.

In 2009, scientists in Europe found that hair follicles produce
small amounts of hydrogen peroxide. Normally this small amount of
hydrogen peroxide is broken down by an enzyme called catalase. As we
age, catalase production is reduced and there is a build up of
hydrogen peroxide, which blocks melanin production by melanocytes.

There are several other things that can cause our hair to turn gray,
including: genetic defects; abnormal hormone production, such as
stress; abnormal body distribution of melanin; and climate factors,
such as pollutants, toxins, and chemical exposure. The time and
speed at which you will gray varies greatly.

As an aside, in Britain, Canada, Australia, Ireland, New Zealand,
and South Africa, the spelling is commonly grey. In the United
States, the preferred spelling is gray, but grey is accepted.